Centrifugal extractor and method of extraction



Dec. 23,l 1941. H. G; scHwARz CENTRIFUGAL EXTRACTOR AND METHOD OF EXTRACTIO Original Filed Deo. 1'7, 1935 3 Sheets-Sheet l /9 l Z0 32 L f 32 l.

INVENTOR WEEE A TTRNEY.

Dec. 23, 1941. I I 1| G; SCHWARZ 2,267,048.

CENTRIFUGAL EXTRACTOR AND METHOD OF EXTRACTION original Filed Den.` 17, .1.935 3 sheets-sheet 2 INVENTOR. /w/y Jay/#wz f ATTORNEY.

' 2,267,048 GENTRIFUGAL EXTRACTO'R AND METHOD 0F EXTRACTION Dec. 23,1941. H. G. scHwARz s Sheng-sheet :s

original Filed Dec. 17, 1935 INVENTOR.

Patented Dec. 23, 1941 CENTRIFUGAL EXTRACTOB AND METHOD F EXTBA'CTION Schwarz Henry G.' Schwarz, Denver, Colo., asslgnor to The Engineering Company, Inc.,

San

Francisco, Calif., a corporation of Nevada Application December 17, 1935, Serial No. 54,795

Renewed May 3, 1937 A 33 Claims.

This invention relates to a juice extractor and more particularly to a. large commercial type of extractor for use in plants packing tomato juice, pineapple juice, and other fruit juices.

All known fruit juice extractors have the fault of expelling with the juice too large an amount of pulp and other ber solids, and other special processes are required to produce either a.y clear juiceor a juice containing the desired amount of pulp or solids.l

Pulp extractors expel' the entire pulp together with the juice and produce an` extract of coarse, heavyV density-rather a mush, making it difficult to extract from this a juice with a. limited amount of fine solids.

An object of the present inventionl is to provide a continuous machine which will produce in (Cl. Mii-'16) one continuous process any desired quality of juice containing any desired amountof pulp or solids of suiiicient fineness to remain suspended in the juice, thus uniformly retaining the original flavor in the juices. Y

Another object of the invention is to provide a continuous machine which will, if desired, produce several dierent grades of juice uniformly varying in the amount of contained solids. When used-upon tomatoes, for example, the machine will, in one process, produce two or three grades of tomato juice, and a heavy pulp without requiring later refining processes.

Other objects of the invention are to provide for more efiicient, more Athorough and quicker extraction of juices, for better and quicker com-l minution of juice-bearing materials including fruits, vegetables and the like, more thorough and quicker opening of juice-containing cells,

more thorough and quicker segregation of juices from residual solids, andto provide a machine into which the juice-bearing materials can be fed and which will extract and separate the juices from thev residual solids more completely and' speedily, as well asto providefor controllingthe comminution ofI the juice-bearing material [and the separation of the juices from. residual solids. v

Another objectof the invention is to reduce or These will become more apparent from thefollowing description.

In the following detailed description -of the invention reference is had'to the accompanying drawings which form a part thereof. Like numerals refer to like parts in alll views of the drawings and throughout the description.

In the drawings:

Fig. l isa vertical section through one iormv of the improved juice extractor.

Fig. 2 is a horizontal section therethrough, y

taken on the line 2-2, Fig. l.

Fig. 3 is a. similar section, taken on the lineV 3-3, Fig. 1.

Fig. 4 is a similar section, taken on theline v.

Fig. 5 is an enlarged detail section through one ofthe rotor ribs of the form of Fig. 1.

. one of the rotor ribs and a double screen arrangeframe III upon which a feed inlet casting VIIl is comminute fruits or vegetables to such 'an extent designed for simplicity, economy, and eiliciency.-

Aseveral grades of -juices of ment.

Fig. 8 Villustrates a vertical section through an alternate form of the invention.

This invention is designed as an improvement on applicants extractor shown in Patent No. 2,054,342, dated September 15, 1936-. Themachine of such patent is primarily designed to obtain a pulpless juice, and, like it, this invention is applicable to the release and extraction of' liquids generally, particularly when entrapped in solids, as for example, within cell walls. The

word juice and its derivatives is used in the appended claims to cover such liquids generally. The present invention will produce such a juice, but can be also regulated to place desired amounts of pulp in the juice or simultaneously produce various amounts 'of pulp content.

The present invention'employs a supporting supported. The casting II may supporta motor basev I2, upon whichv a suitable driving motor may be mounted. The rotorof the inventionl consists of an open bottomed, bell-shaped rotor I3 preferably formed integrally wltha concentric, upwardly extending vrotor shaft Il. The

shaft- I4 terminates in a shaft collar4 I5, to which v a motor shaft I6 may beisecured.

At the bottom of the frame .I0 is a bearing spider I1, provided at its. middle with ya suitable ball bearing I8. The bottom of the rotor bell I3 -is closed by means of a bearing platel I9, from which a stub shaft 20 projects downwardly into l the bearing I3. An aligning bearing 2| for the tional stages or diameters.

shaft 4 is carried on the feed casting It is'desired to call attention to the fact that the rotor |3 is formed with a series of sections or steps of increasing diameters,' as the bottom is approached, which give diierent stages of action on the juice. As illustrated, the rotor is provided with two stages 22 and 23. It could, if desired, be increased in length, and have addirotor is provided with'a series of .ribs 24 which are inclined on a gradual spiral about the rotor.`

The ribs 24 of each stage terminate at their bottom in an outwardly extending conical shelf 25, which directs the pulp onto the next lower stage.

The first stage 22 is surrounded by a downwardly extending juice sk irt 26 which in turn surrounds a cylindrical screen 21. The lower edge of the screen 21 terminates on a conical, annular shredding bur 28, from which a second screen 29 extends downwardly about the second stage 23.

'I'he second screen 29 is surrounded by a second, downwardly extending skirt 30 which directs the juices passing through the screen 29 downwardly into a juice channel 3| surrounding the bearing spider I1. The juice is led from the channel 3| through any suitable juice conduits 32.

The inclined shelf 25 of the rotor is positioned opposite the shredding bur 28 and at this point is provided with a series of small shredding teeth 33. On the top of the rotor |3, a series of radial shredder blades 34 are positioned and immediately below these blades area series of shredder teeth 35. 'The blades 34 and the teeth 35 are positioned opposite a vertically grooved, shredi ding ring 36 carried in the frame l0.

The skirts 26 and 30 serve to back up the screens 21 and 29 to prevent undue pressure from forcing these screens outwardly. Since the skirts must bear against the screens, they are provided with a series of closely spaced, juice channels 31 which serve to allow the juice to pass through the screens. v f

In use, the fruit or other material from which the juice is to be extracted is fed into the feed casting from any suitable supply conduit. The first shreddingblades 34 cut the fruit into rather coarse pieces without producing ne pulp. These pieces are sumciently iine, however, to allow the juice to be easily expelled. These coarse fruit particles then pass through between the shredlding teeth 35 and the shredding ring 35 which Each stage of the tain' the heavier solids and stringy bers and direct these downwardly onto the inclined shelf .25 of the second shredder.

' The material entering the rst stage is carried `around the periphery `for only a fraction of a inner face of the screen; and the pure juice itself which passes immediately through the screen.

The accumulation of the fine solids on the screen builds up to a thickness sulcient to prevent forcing the pulp through the screen.A When this accumulation reaches an excess thickness 'the ribs of the rotor scrape it from place and force it downwardly while new material immediately collects on the screen and the process repeats itself. This fine layer of solids acts as a ilter for the expelled juice and prevents an excess of ne pulp passing through the screen.

The heavier solids upon reaching the second lshredder between the ribs 33 and the grinding down the juice channels s1 in the skirts 2s and 30. The .juice from the first stage can be collected from a separate juice channel 39 while the juice from the second stage is collected from the channel 3|, should a classiilcation of the juices be desired, or both juices may be allowed to flow to the channel 3| ,through an outer juiceshell 40 if desired. i

The pulp passes from the ilnallstage 23 through a pulp throat 4| between the lower extremity of the rotor and a lowerscreen band 42. It then drops through the spider |1 to any suitable collector. The passage space of the pulp throat 4| is controlled by the size of the bearing plate I9 so as to hold the pulp back until the required percentage of juice has been extracted. If this pulp throat is relatively narrow, the pulp will'be held back to build up-a pressure behind the ilnal screen for the extreme extraction of juice.

v In Figs. 6, 7, and 8, a slightly alternate form of the invention is illustrated. In this form, the rst extraction stage of the rotor is indicated at 43, and the second stage at 4 4. 'Ihe rotor is surrounded by a plurality of annular shells such' as indicated at 45, 43, and 41. The lower shells such'as those shown at 45, and 41 each are formed with a peripheral juice channel 48 from which suitable pipe outlets lead. 'Ihese shells are preferably formed in two halves bolted to-` about the rotor so as to 'separate any desired number of different grades'of juice. 4

The screens 5| can be of different mesh, fo lnstance'the upper screen may be of very ne mesh, and the lower -screens of increasingly coarse mesh. yThis will produce a. clearv juice at the topof the machine of an exceedinghf ne clarity and a coarser juice at the bottom with a revolution.v This avoids breaking up thev finer fruit cells on the screen and thus prevents forclarge amount of pulp.

In thisform the rotor stages are provided with hooked or grooved ribs 52, the grooves being on the forward face of each rib, as shown in Figs. 6 and. 7. These vgrooves provide. channels yfor holding the coarser pulp and carrying it rapidly fine string? solids which are deposited on the to the bottom of the machine. They also serve as efficient summers to scrape down the layer of vriiess.

pulp onthe screens to a constant uniform thick- 'I'his form also is provided with` an adjustment vfor the pulp discharge throat. This adjustment comprises cutting a series of notches 53 in the lower periphery of the rotor, there being one -notch immediately ahead of each rib.l A control ring M surrounds the bottom bearing plate of the rotor. The control ring is provided with registering notches 55 which can be brought into alignment with the notches 53 to allow a full opening thereof, or which can bebrought out of alignment to partially close this opening as in- 'dicated in Fig. 6. This enables the operator to up by means-of a coarse screen as indicated at Y 56 in Fig. '7.

in recovery of greater amounts of juices. Some juices, it should be emphasized, particularly some potable. nutritional juices and perhaps others also, should contain certain solid nutritional ma.- terial in very nely divided form as well as the liquid portion of the juice.

The ribs 24 and 52, and ribs similar thereto in whatever modification or stage they may pre- The machine illustrated in Fig. 1. gives two l juice classiiications. The machine illustrated in Fig. 8 gives three juice classifications. `It is desired to be understood that by increasing they length of the rotor or by increasing the number oi shells 46 and screens about the rotor, any desired number of classications may be obtained. y

Many advantages accrue from the structure of the 'machine and from the nature of the inven-A tion. For example, comminution of the material to free the juice normally retained withinthe juice cells and separation of such juicel are both made speedier and more complete. Comminution -to a'very fine degree in a single comminution step requires subjection thereto of the material being comminuted for a longer period of time than is necessary to get the same or better results sent, rotate with the rotor and with respect to the screen surrounding them, and also with jrespect to the layer of comminuted solids built up on the screen and which acts as a iilter.l The ribs at the high operating speed of the machine, centrifuge material resulting from the comminution step and throw it obliquely and forcibly' against the inner face of such ltering layer by their centrifugal eiect thereon. The velocity thus imparted to the juices aids the juices to speedily penetrate the filtering layer and pass to the outside of the screen, and it may cause some erosion of the filtering layer, particularly since the impact is oblique to the inner face thereof.

Such ribs urge the -material downwardly against the resistance due to the restricted size of the throat outlet for the solid residues, and a similar effect may be due to the blades 34 or blades similar thereto in conjunction with the A restricted outlet. This results in setting up a rial passing through the subsequent comminugion stage is lessened by the removal of the freed uice. Forcing the separation of the juices from the residual solids makes such separation much speedier and more complete. This is of very great importance between comminuting steps,

because it prepares the material which was comminuted in an earlier comminutibn step very speedily for comminution in the subsequent comminution step, and thus aids a small machine to .produce very speedily a great output and -also in,and if such mass is wet enough, which is the ration and permits the speedy removal of residual solids from the machine. I'hus, the time required for comminution is reduced as is the time required for separation of the freed-juice, `and both are made more complete., The combination of both' results not only in lessening the time .required for the.l recovery of the juices, but also pressure zone in which the material is com' pressed in a juice lseparation stage after such material has been comminuted a'nd in which it is compressed while being comminuted. The compression aids in thev separation of the liberated juice from the residual solids. The combination of such ribs which are within a juice separation stage with therestricted outlet for the residual solids creates pressure to compress the ,materiall within that stage. The same combination of parts exerts pressure on material'in a later juice separation stage because such1 later stage is within the pressure zone formed by such combination. Likewise, the same combination of parts exerts pressure on material undergoing comminution in a later comminuting stage because such stage is also .within such pressure zone. Furthermore, considering the bladesy 34 and the restrictedv outlet for the residual solids as" the combination means for'producing a pressurev zone, all comminutionv stages and juice separating stages therebetween will be in such pressure zone.

The degree vof pressure applied can be varied and controlled by adjustment of the adjustable outlet for the residual solids. Not only does the pressure compress the material in the juice separation stage, but that same application of pressure isreiiected back and so coordinated as to compress the material both while and after being subjected to comminution. The pressure has its effect on the comminution which may accordingly be varied and-controlled by adjustment of the pressure.

Another advantage is that the space between the cooperating elements of a comminuting stage will be lled and bridged over by the mass there- .case with most fruits and vegetables, it willform what amounts to a liquid seal between the cooperating comminuting elements. As will be apparent by inspection of Fig. l, for example, the

liquid seal between the cooperating comminuting elements 35 and 36 prevents access of much air to the material after the 'inside thereof is exposed and consequent substantialv loss .by oxidation of vitamins or ilavoring or other food materials present, so that the resulting juice is of better quality.

Some other advantages of the machine are that it can operate continuously, and that it is not necessary. to stop the machine to remove residual solids because they are automatically expelled from the machine as the operation continues.

While a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied, within the scope of the appendedA claims, without departing from the spirit of the invention.

Havingthus described the invention, whatis claimed and desired Secured by' Letters Patent `is:-

1. A juice extractor comprising: a vertically mounted rotor; a series of successive cylindrical surfaces on said rotor, the diameter of said successive surfaces increasing as the bottom of said rotor is approached; a screen surrounding each of said surfaces, said screens also increasing in diameter as the bottom is approached; peripheral juice channels surrounding said screens to collect the juices passing therethrough; ribs projecting from each of said surfaces, said ribs being inclined so as to direct material downwardly as said rotor rotates; a conical portion surrounding said rotor and connecting a surface of one diameter to the next lower surface of greater diameter; and ribs extending from said conical portion. I

2. A juice extractor comprising: a vertically mounted rotor; a series ofsuccessive cylindrical surfaces on said rotor, the diameter of said successive surfaces increasing as the bottom of said rotor is approached; a screen surroundingeach of said surfaces, said screens also increasing in diameter as the bottom is approached; periphabout said conical portion so as to impart a shredding action on material passing from one cylindrical surface to the adjacent cylindrical surface.

3. A juice extractor comprising: a vertically mounted rotor; a series of successive cylindrical surfaces on said rotor, the diameter of said successive surfacesincreasing as the bottom of said by said bearing spider; a bell-shaped rotor positioned in said frame; a bearing plate closing the bottom. of said rotor; a shaft extending from said bearing plate downward into said bearing; a vertical rotor shaft extending upwardly from said rotor through said feed chamber; said rotor having two cylindrical surfaces, the lowermostv surface being of a large diameter; a screen surrounding each of said surfaces; a'juice collecting skirt surrounding each of Said screens; and a juice channel for independently receiving the juice from each of said skirts.

5. A juice extractor comprising: a supporting frame; an annular band at the top of said supportingframe; a feed chamber supported above said band; a bearing spider supported in said frame below said band; an axial bearing carried by said bearing spider; a bell-shaped rotor positioned in said frame; a bearing plate closing the bottom of said rotor; a shaft extending from said bearing 'plate downward into said bearing; a vertical rotor shaft extending upwardly from said rotor through said feed chamber; said rotor lhaving two cylindrical surfaces,.the' lowermost surface being of a larger diameter; a screen surrounding each of said surfaces; a juice collecting skirt surrounding each of said screens; a l

- prising: a vertical series of cylindrical members rotor is approached; a screen surrounding each of said surfaces, said screens also increasing in diameter as the bottom is approached; and peripheral juice channels surrounding said screens t collect the juices passing therethrough; ribs projecting from each of saidsurfaces, said ribs being inclined so as to direct material downsurrounding said drum; a screen carried by each of said members around said drum; and'means for independently collecting the juices which pass through eachI of said screens; a juice channel about each of said members; a passage for conducting the juice of the next above member to the `juice channel of the-next below member; means for drawing oif the juice `from each of said channels; an upper cylindrical surface on said rotary drum; a lowercylindrical surface on said rotary drum of alarger' diameter than the upper cylindrical surface thereof; a conical shelf connecting said two surfaces; and an annular grinding member surrounding said conical shelf.

'7. In a juice extractor bladed, rotary drum, means for obtaining a classification of the juices extracted therefrom comprising: a vertical series of cylindrical members surrounding said drum; al screen carried by each of said members around said drum; and means for independently collecting the juices which pass through each of said screens; and a f series of inclined ribs formed on said drum, each of said ribs having a longitudinal groove in its forward face.

8. In a juice extractor having a vertical, rotary, ribbed drum within a cylindrical screen; means for retarding material from passing from between said screen and said drum comprising: a projecting lower extremity ony said drum; a coacting annular surface'about said projecting portion so as to provide a restricted annularpassage about the lower extremity of said drum; means for varying the opening of said passage comprising a series of vertical grooves formed in said projecting portion; and a rotary annular ring having coacting .having a cylindrical, i

grooves by means oi' which the opening of the grooves of said projecting portion may be con.- trolled. i

9. A machine for extracting juice from pulp comprising; a vertically mounted cylindrical rotor; a plurality of connected, cylindrical surfaces on said rotor, the diameter of each successive surface, as the bottom of said rotor is approached, being greater than that of the next above surface; a connecting surface connecting the adjacent cylindrical surfaces; a stationary cylindrical screen spaced from and surroundingeach of said cylindrical surfaces; means for collecting the juice passing through said screen; means connecting said screens and spaced from said connecting surface to provide a continuous passage for pulp from one surface to the next lower surface.

Y 10. In a machine for extracting juice from pulp comprising: a vertically mounted cylindrical rotor; a casing surrounding said rotor; a plurality of connected, cylindrical surfaces on said rotor, the diameter of each successive surface, as the bottom of Vsaid rotor is approached, being greater than that of the next above surface; a

connecting surface connecting thel adjacent cy' lindrical surfaces so as to provide a continuous passage for said pulp downwardly over said surfaces; spaced-apart ribs projecting from said cylindrical surfaces, said ribs extending downwardly and rearwardly from the direction of rol tation so that as said rotor rotates they will act to force the pulp downwardly.

1l. A machine for extracting juice from'pulp comprising: a vertically mounted cylindrical rotor; a casing surrounding said rotor; aplurallty of connected, cylindrical surfaces on said rotor, the diameter of each successive surface, as the bottom of said rotor is approached, being greater than that of the next above surface; an outscribed comprising: a vertically mounted rotatable drum of less diameter at its top than at its bottom, the upper diameter being continued downwardly on said drum to form an upper cylindrical portion, the lower diameter being con- 1 l tinued upwardly on said drum to form a lower cylindrical portion; a conical portion joining saidtwo upper and lower portions together and shredl. ding means carried by said conical portion for shredding-material passing from the upper to the lower portions.

13. A juice extractor of the type described 00- comprising: a casing;'a vertically mounted rotemvo able drum within said casing, said drum having a less diameter at its top than at its bottom, the

upper diameter being continued downwardly on.

said drum to form an upper cylindrical portion, 63

the lower diameter being continued upwardly fon' -said drum to form a lower cylindrical portion; a' conical portion joining said two upper and lower portions together; shredding means carried by said conical portion coacting with means on said casing for shredding material passing from the upper to thelower portions; and adjustable` means at the lower extremity of said drum coacting with said drum and said casing for controlling the discharge of pulp from said extractor.

14. A ljuice extractor comprising: a vertically mounted rotor; a series of successive cylindrical surfaces increasing in diameter as the bottom of projecting from each of said surfaces, said ribs being inclined so as to direct material downwardly -as said rotor rotates; a conical portion surrounding said rotor and connecting a surface pulp i'roml said screens, and to form scoop-like cutting faces.

16. A juice extractor comprising: a rotor having one end higher than the other, cutters on said rotor and so inclined with respect-thereto that the upper ends of said cutters are forwardly of the lower ends thereof in the direction of rotation of said rotor, said cutters each forming a concavity forwardly thereof, and a screen about said rotor and cutters; whereby juice-bearing material will be subdivided and separated into a heavier fraction which moves downwardly in said concavities, a lighter fraction which is deposited on the inner face ofthe screen, and juice which passes through the screen.

17. A juice extractor comprising a rotor; a stal tor about and spaced from said rotor; comminuting means comprising a part on said rotor and a part on said stator,v said parts being closely adjacent eachother to form a narrow passage therebetween and cooperating with each other to finely comminute juice-bearing material passing therethrough:l a screen about said rotor; and means ,to build up a filtering layer` of resulting finely divided solid material on said screen and to limit the thickness thereof to a predetermined maximum less than the cross-sectional area betweensaid rotor and screen, comprising means to move the resulting finely divided material longitudinally between said rotor and screen and means to rotate said rotor at a speed-to actuate said 50 finely dividing means and to throw said moving material by centrifugal action against said screen. t

18. A Juice extractor comprising: a series of cylindrical screens above each other, separate means to comminute material entering said screens, whirling means `within said screens, a lowercomminuting means and a lower whirling means having greater comminuting and whirling effects, respectively, than similar means thereabove, means to lead comminuted solid`material remaining within an upper of said screens through a lower comminuting means into a lower of said screens after liquid therewith has passed through said upper screen, and means to lead liquids passing through said screens away from the remaining solid material.`

19. A juice extractorI comprising: a series of cylindrical screens above each other, separate means to comminute material entering said screens, whirling means within said screens, a

lower comminuting means and a lower whirling means having greater comminutingand whirling eii'ects, respectively, than similar means there-.-

above, means to leadcomminuted solid material remaining within `an upper of said screens through a lower communiting means into a lower of said screens after liquid therewith has passed through said upper screen,` and peripheral juice channels surrounding said screens to collect the juices passing therethrough and lead them away from the solids remaining within said screens.

20. A juice extractor comprising: a series of cylindrical screens above each other, separate means to comminute material entering said screens, whirling means within said screens, a lower comminuting means and a lower whirling means having greater comminuting and whirling effects. respectively, than similar lmeans thereabove, means to lead comminuted solid material remaining within an upper of said screens through` a lower comminuting means into a lower of said screens after liquid therewith has passed through said upper screen, means to compress saidled material while being comminuted, and means to lead liquids passing through said screens away from the remaining solid material.

21. A juice extractor comprising: means to comminute juice-bearing material, means to compress the resulting comminuted material, and means to coordinate said compressing means with said comminuting means to compress said material both while and after being subjected to said comminuting means.

22. In a juice extractor of the class described, a rotary drum, a rib projecting outwardly from said drum, and a cylindrical screen surrounding said drum and rib, said rib forming a longituof rotation being inclined forwardly to form conjointly with the surface of the rotor a forward concavity transverse to the direction of rotation and of such depth as to be capable while rotating of retaining material between said rotor and the outer end of said rib, whereby, when said comminuted material is fed into said space Ibetween said stator and said-rotor while rotating,

` due to centrifugal effect, said solids will have a greater tendency than said liquid to be retained in said concavity, and means to rotate said rotor and ribat a speed to produce said centrifugal effect.

24. In a juice extractor, a rotor, a rib on said rotor, a stator about said rib and said rotor, the face of said rib which is forward in the direction of rotation being inclined forwardly to form a forward concavity of such depth as to be capable while rotating of retaining material between said rotor and theouter end of said rib, whereby, when comminuted solids mixed with liquid are between said stator and said rotor while rotating, due to centrifugal effect, said solids will have a greater tendency than said liquid to be retained in said concavity, said face of said rib being oblique to the direction of rotation to direct said solid material along said concavity, and means to rotate said rotor and rib at a speed to produce said centrifugal eiiect.

25. In a juice extractor, a rotor, a screen about said rotor forming an annular space therebetween, a rib on said rotor in said space, the face rotation boing inonned forwardly ro form a forward concavity of such deptlnas to be capable of retaining material at a locusbetween said rotor and the outer end of said rib while rotating, whereby, due to centrifugal effect, solids will have a greater tendency than liquid to be retained in said concavity, said face of said rib being oblique to the direction of rotation to direct said solid material along said concavity, means to rotate said rotor and rib at a speedvto producesaid centrifugal effect,l said annularV space leading to an exit passage, and means to adjustably restrict said exit passage.

26. The method of extracting juice from juicebearing material, which comprises: treating said material to an earlier comminuting step to open some but not all of the juice cells and thereby free juice therein; removing by centrifuging suiiicient of the free juice from the resulting mass to render solids therein easily comminutable; treating said solids to a later comminuting step to open still unopened juice cells to free juice therein; and removing by 'centrifuging juice freed by said later comminuting step.

27. The method of extracting juice from juicebearing material, which comprises: treating said material to an earlier comminuting step to open some but not all of the juice cells and thereby free juice therein; removing by centrifuging sufficient of the free juice from the resultingmass to render solids therein easily comminutable; treating said solids toa later comminuting step to open still unopened juice cells to free juice therein while compensating for reduction in volume due to removal of juice; and removing by centrifuging the juice freed by said later comminuting step.

28. The method of extracting juice from juicebearing material, which comprises: treating said material to an earlier comminuting step to open some but not all of the juice cells and thereby free juice therein; removing by centrifuging sufiicient vof the free juice from the resulting mass of soia rib which 1s forward in the direction of 75 to render solids therein easilycomminutable; treating said solids to a later comminuting step to open still unopened juice cells to free juice therein; removing by centrifuging juice freed by said later comminuting step; and preventing access to the materials treated and produced during said sequence of steps of air sutllcient to deteriorate resulting juice.

29. 'I'he method of extracting juice from juicebearing material, which comprises: grinding said material, immediately centrifuging the resulting ground mass to separate resulting coarser solids first mentioned grinding step, immediately centrifuging the resulting ground mass to separate resulting coarser solids from resulting freely flowing juice, moving the ground material substantially parallel to the axis of centrifuging 'during centrifuging, and restricting such movement of the material to create pressure other than the pressure incident to centrifuging and grinding.

30. A juice extractor comprising: a plurality of spaced centrifugal separating means comprising a rotor and a stator about and spaced from said rotor, means .to lead ci juices separated thereby, each separating means having means to forward solid material therethrough, means on said stator and rotor to comminute juice-bearing material and to forward the resulting comminuted material to abprior separating means. meanson said stator and rotor to comminute more ilnely the solids forwarded through said prior separating means and tol forward the resulting comminuted material to another said separating means, said last-mentioned Separating means having an exit passage for the finally separated solids, and means to vary said exit passage to cause and control back pressure on the material undergoing treatment.

31. A centrifugal juice' extractor comprising: a rotor; a stator about and spaced from said rotor; commuting means comprising apart on said rotor and a part on said'stator; means to move the comminuted material during rotation4 a rotor; a stator about and spaced from said ro tor; comminuting means comprising a part on said rotor and a part on said stator. said parts being closely adjacent each other to form a. narrow. passage therebetween-and cooperating with each other to nely comminute juice-bearing material passing therebetween; a screen about said rotor; means to move the comminuted mate-4 rial during rotation in a path away from said p comminuting means through saidscreen substantially parallel to the axis oi rotation; and means to adjust the pressure between said comminuting means and the material being comminuted thereby and the pressure exerted on the comminuted material within said screen, comprising means to restrict such movement of the material to create pressure other than the 'pres-'- sure incident to centriiuging and comminuting.

33. In a juice-extractor: an annular screen; means to nely comminute juice-bearing material, to feed the finely comminuted material into said screen, and to exclude coarse pieces therefrom; a rotor within said screen; a rib within said screen on said rotor to centrifuge mixed liquid and nely divided solids, the i'ace'ot said rib which is forward in the direction of rotation being inclined to iced said material through said screen substantially parallel to the i axis of centrifusing during centrifuglng, the outer face of said rib being spaced trom said screen to permit build-up on said screen of a lter bed oi iinely divided solid material only; and means to rotate said rotor yand rib suiilciently tast to throw said moving material outwardly by centrlfugal action.

, HENRY G. SCHWARZ. 

